Sewage backwater relief vent

ABSTRACT

Disclosed is a household sewage collection system employing a backwater relief vent. The relief vent is an externally threaded cylindrical body adapted to replace the clean-out plug and has a centrally located aperture. The aperture is closed with a nonthreaded plug which prevents the escape of sewer gas but is unseated by back pressure exerted thereon to vent any backwater fluid at ground level and thus prevent backwater from rising to the level of the sewer receptacles.

Unite States Patent 1191 berholtzer SEWAGE BACKWATER RELIEF VENT Inventor: Jene V. Oberholtzer, 10005 Newcombe Dr., Dallas, Tex. 75228 Filed: Sept. 18, 1973 Appl. No.: 398,408

, 4/DIG, 7, 13S/89, 137/236, IS7/247.11 Int. Cl E031` 5/08 Field of Search 4/1, 136, 129, 133, 106,

4/216-221, 286, DIG. 7, 287, 293, 295; 138/89; 137/236, 247.11

References Cited UNITED STATES PATENTS 8/1913 Raenstierna 4/204 X 8/1914 Schmidt 4/204 X f 7/1957 Gast 138/89 UX U.S. C1 4/219, 4/211, 4/295, i

[451 Dec'. 10, 1974 3,148,708 9/19154A Paneua ..138/89 3,229,707 1/1966 suenan 137/236 3,285,289 11/1966 Titus ..138/89 3,610,287 10/1971 Angood 13s/89 Primary Examiner-Henry rK. Artis Attorney, Agent, 0r Firm-Jack A. Kanz [57] ABSTRACT Disclosedis a household sewage collection system employing a backwater relief vent. The relief vent is an externally threaded cylindrical body adapted to replace the clean-out plug and has a centrally located aperture. The aperture is closed with a non-threaded plug which prevents the escape of sewer gas but is un.- 1

seated by b ack pressure exerted thereonto vent any backwater fluid at ground leveland thus prevent backwater from rising to the level of the sewer receptacles;

4 Claims, 3 Drawing Figures 1 y SEWAGE BACKWATER RELIEF VENT This invention relates to sewer system relief vents. More particularly it relates to systems and apparatus for venting backwater from sewer collection systems and preventing backwater from overflowing through household sewer receptacles.

Conventional sewage disposal systems for ordinary l household use comprise a plurality of sewage and sewage water receptacles, such as bathtubs, lavatories, sinks and the like, which drain by gravity into a common sewage collection line which then in turn feeds directly into a sewer main. Each of the individual sewage receptacles ordinarily employs a conventional S-trap to prevent sewer gas from escaping from the sewer system into the receptacle.

Sewer water feeds by gravity from each of the receptacles into the collection line and to the sewer main. Accordingly, the o'nly pressure exerted on the sewage system a`t any point between the` collection point'and injection into the sewer main is the weight of the flowing water. Conventionally there is a vertical vent pipe installed between the traps and the sewer main to prevent sewer gas from backing through the traps and to insure that the sewer system is maintained at atmo spheric pressures. The conventional sewer system as described above also ordinarily includes a conventional clean-out port in the collection line to provide access to the sewer collection system so that the system may be mechanically cleaned if accidentally plugged.

Since the individual sewage collection system and the sewer main rely on gravity feed for flow-of sewage water away from the collection point, blockage or overloading of the sewer main can produce devastating results. For example, if the sewer main is blocked vdownstream from the collection system sewage in the main from upstreaml sources will be diverted `to the collection systems nearest to the blockage and flow backward through the individual traps and into the` sewage receptacles. v Y

Previous attempts to prevent suchy backwater flooding commonly take the formof backwater traps which, in essence, are one-way valves between the sewer collection points and the interconnection between the collection system and the main. Accordingly, such traps allow sewage to flow only in the direction of the main and prevent back flow from the main into thecollection system. Unfortunately Asuch backwater traps are not totally effective and, since they are usually mechanical, are subject to deterioration and themselves increase the likelihood of blockage of the collection sys tem. Furthermore, if themain is clogged and the backl water valve closed, no vent is provided to relieve collection of sewage in the individual collection systems. Thus sewage will be vented by gravity through the lowest receptacle in the household system and cause it to overflow.

ln accordance with the present invention a vent is provided which is designed to replace the plug ordinarily used to cap the clean-out port provided in conventional sewage collection systems. The 'relief vent of the invention isvd'esigned to be positioned at or near ground level, thus below the lowestreceptacle in the collection system. Thev vent is opened by the `pressure of backwater alone to prevent any backwater from rising above ground level between the receptacles and the sewer main. Accordingly, any backwater diverted to the collection line from the main line will be vented through the relief vent of the invention before entering the household system. Likewise, if the household collection system is plugged between the clean-out port and the main, all sewage and water from the collection system will be vented at ground level and will not be allowed to backup to the level of the lowest receptacle. Accordingly,'the vent plug of the invention prevents any possibility of backwater being diverted from the main into the household system and also prevents the flooding of the household system through the lowest receptacle if the collection system is plugged. The vent may be convenientlyl inserted as a replacement for the plug in a conventional clean-out port. It is also automatically activatedwithout providing a potential blockage hazard to the system itself.

Other advantages and featuresof the invention will become more readily understood when taken in connection with the appended claims and attached drawings in which:

FIG. l isa sectional view of the preferred embodii ment of the relief vent of the invention;

FIG. 2 is a top plan view of the relief vent of FIG. l;

and

FIG. 3 is a schematic illustration of a conventional household sewagecollection system employing the re-`.

lief vent of the invention.

A conventional household sewagecollection system is partially illustrated in FIG. 3. The conventional system usually comprises a plurality of sewage collection receptacles such as a lavatory l0. Effluent from the lavatory drains by. gravity through 'a drain` line 1l, trap 12 and into a sewagecollection line 13. Othersewage collection sources (not illustrated) also feed into sewage collection line 13.- An open line 14. provides a vent from the collection line 13 to atmosphere. The vent 14 is usually a vertical pipe open at the top above or near the upper level of the housing structure. The purpose of vent 14 is. to allow the escape of sewer gas from the collection line 13` and to insure that gas pressure in collection line 13 remains at atmospheric. The sewage collection line 13 provides means to conduct the sewage collected from the various receptacles into a sewer main. The collection line 13 is at or below ground level and drains by gravity toward the main.

The ordinary collection system also includes a cleanout port 15 at or near ground level between the sewage collection receptacles and the main line. vThe purpose of the clean-out port is to provide easy access to the collection line 13 for mechanical cleaning when necessary. Ordinarily clean-out port 15 is closed with a threaded plug which can vbe mechanically removed to allow access to the sewer system..

ln accordance with the present invention the conventional plug in clean-out port 15 is replacedv by a relief vent plug. The relief vent plug of this invention is illustrated at 16 in FIGS. l and 2.

The vent plug 16 comprises a cylindrical body 17 threaded on its vertical exterior surface -with conven-` A, tional male pipe threads v18 to mate with the con-ventional female threads in the conventional clean-.out port l5. The top surface of the body '17 is flat'but is provided with a plurality of ir'idevnturesv 19 kadapted to mate with the tongs of a conventional sewer plug wrench for screwing plug 16 `into and out Vof a conventional clean-out port. f

A centrally located cylindrical aperture 20 passes vertically through the body 17 concentric with the exterior vertical surface thereof. ln the preferred embodiment the body 17 includes a groove 21 on the top sur-v face which has outwardly sloping outer surfaces 21a concentric with the aperture 20 as illustrated in FIG. l. It will be observed that the major portion of the wall of the aperture 20 is vertical and concentric with the exterior walls of the body. The top of the aperture, however, is expanded to join groove 21 below the level of the top surface of -the body 17.

A plug 22, having external dimensions conforming to the internal dimensions of aperture 20 and groove 21, is positioned within the aperture 20 and groove 21 as illustrated in FIG. 1. The plug 22 preferably mates with the groove 2l and aperture 20 to provide an easily removably sliding' plug which is not bound in the aperture. However, the expanded portion 22a of plug 22 rests in groove 21 and provides a gas tight seal merely by the weight of the plug 22 resting on the walls 21a and bottom of groove 21'. ln the preferred embodiment the lower end of plug 22 extends'slightly below the lower surface of the plug body.

The entire vent plug as illustrated in FIGS. 1 and 2 ispreferably constructed of a durable but lightweight material such as plastic or the like. The material of the plug should preferably be formed of a non-corrosive non-oxidizable material so that the plug 22 does not become bound in the aperture 20. Furthermore, as illustrated in FIG. l, thetop surface of plug 22 is preferably co-planar with the top surface-of the cylindrical body 17.

lf desired, flexible retaining means such as a line 25 may be attached to the plug 22 and to the body 17 to prevent loss of the plug during installation or use. The line 25 should be of sufficient length tol permit plug 22 to be completely removed from the aperture 20.

In use the assembly of FIG. l is substituted for the conventional clean-out port plugas illustrated in FIG. 3. vlt will be observed that when placed in a vertical position in the clean-out port l5 in an otherwise conventional system, the plug 22 is retained within the system merely by gravity but provides an effective gas seal by the weight of the plug 22 being supported by the sides and bottom of groove 21. In normal` use sewer water does not rise in the'clean-out port 15 and the relief vent plug is not affected. However, if the collection line 13 becomes plugged downstream from the clean-out port or if the sewer main becomes overloaded or plugged downstream from the junction of the collection line 13 and the sewer main, sewer water will accumulate within the collection line 13. As the amount of sewer water increases the level thereof will rise at equal levels in all receptacle lines and the -vent 14. As the sewage water rises a hydrostatic head of pressure builds up in the collection system. Since the clean-out port is located at or near ground level and below the level of the lowest receptacle, the hydrostatic pressure will be exerted against the relief plug 22. When the pressure becomes greater than the weight of plug 22, plug 22 will be elevated off its seat and allow the sewer water to escape through the aperture 20. Since plug 22 is retained within aperture merely by its own weight, the hydrostatic pressure allowed to buildup in the collection line 13 need only be sufficient to lift the weight of plug 22. Furthermore, since the clean-out port is at ground level (below the level of any sewage receptacle within the household system), sufficient hydrostatic pressure will accumulate in line 13 to remove plug 22 from the aperture 20 before the sewage water reaches the level of any receptacle. Accordingly, all fluid accumulating in the collection system above the level of the clean-out port 15 will be vented through the aperture 20.

It should be noted that after the blockage is relieved the plugv22 need merely be replaced within the aperture 20 and the system is again in normal working condition. lt should be also noted that the relief vent disclosed replaces the cap plug in a conventional cleanout port. The vent plug may, of course, be removed as desired to provide access for mechanical clean-out purposes in the conventional manner.

While the invention has been disclosed with reference to a household sewage system, it will be readily appreciated that the system may be employed in any single or multi-family dwelling as well as in commercial establishments. Furthermore, the relief vent plug of the invention can be constructed quite inexpensively and substituted for the plug cap in a conventional cleanfout port. Therefore, ver-y little expense or labor is required to provide the advantages of the invention in an otherwise conventional system.

Although the invention has been described with particular reference to a specific embodiment thereof, it is to be understood that the form of the invention shown and described is to be taken as the preferred embodiment of same, and that various changes and modifications may be resorted to without departing from the spirit and scope of the invention as defined'by the appended claims. y

What is claimed is:

1. A relief vent and plug comprising:

a. a first cylindrical body with male threads on the veitical exterior surface thereof and having a centrally located aperture passing vertically therethrough; and y b. a second cylindrical body removeably positioned within said aperture substantially sealing said aperture and retained therein only by gravitational force exerted on said second cylindrical body;

wherein the bottom portion of said aperture is substantially cylindrical and the top portion' thereof is expanded to form a recessed groove in the top face of said first cylindrical body, concentric with said cylindrical portion of said aperture, and the external surface of said second cylindrical bodyis conformed to mate with Athe surfaces of said aperture.

2. The relief vent and plug defined in claim l wherein the plane of the top surface of said second cylindrical body is substantially coplanar with the plane of the top surface of said first cylindrical body and the lower end of said second cylindrical body extends below the plane of the bottom surface of said first cylindrical body.

3. The relief vent and plug defined in claim l including flexible means interconnecting said first cylindrical body and said second cylindrical body, .said flexible means being of sufficient length to permit said second cylindrical body to be completely removed from said aperture.

4. ln combination:

a. a plurality of sewage collection receptacles;

b. a sewage collection line in fluid communication with each of said receptacles and with a sewer main;

centrally located aperture therethrough; and

ii. a second cylindrical body removeably positioned within said aperture substantially sealing said aperture and retained therein only by gravitational force exerted on said second cylindrical body.

passing vertically 

1. A relief vent and plug comprising: a. a first cylindrical body with male threads on the vertical exterior surface thereof and having a centrally located aperture passing vertically therethrough; and b. a second cylindrical body removeably positioned within said aperture substantially sealing said aperture and retained therein only by gravitational force exerted on said second cylindrical body; wherein the bottom portion of said aperture is substantially cylindrical and the top portion thereof is expanded to form a recessed groove in the top face of said first cylindrical body concentric with said cylindrical portion of said aperture, and the external surface of said second cylindrical body is conformed to mate with the surfaces of said aperture.
 2. The relief vent and plug defined in claim 1 wherein the plane of the top surface of said second cylindrical body is substantially coplanar with the plane of the top surface of said first cylindrical body and the lower end of said second cylindrical body extends below the plane of the bottom surface of said first cylindrical body.
 3. The relief vent and plug defined in claim 1 including flexible means interconnecting said first cylindrical body and said second cylindrical body, said flexible means being of sufficient length to permit said second cylindrical body to be completely removed from said aperture.
 4. In combination: a. a plurality of sewage collection receptacles; b. a sewage collection line in fluid communication with each of said receptacles and with a sewer main; c. a clean-out port in said sewage collection line below the level of the lowest receptacle and between the receptacles and said sewer main; and d. a relief vent plug closing said clean-out port, said relief vent plug comprising: i. a first cylindrical body with male threads on the vertical exterior surface thereof and having a centrally located aperture passing vertically therethrough; and ii. a second cylindrical body removeably positioned within said aperture substantially sealing said aperture and retained therein only by gravitational force exerted on said second cylindrical body. 